KARACHI (Reuters) - Police in the Pakistani city of Karachi have arrested an al Qaeda operative who is on the United Nations sanctions list, a police official said on Friday.

Pakistan has been under pressure to crack down on Islamist militant groups and launched a renewed operation against many of them in 2014, when al Qaeda chief Ayman al-Zawahri announced the formation of a new wing, al Qaeda in the Indian subcontinent.

The region, stretching across countries including Pakistan, India and Bangladesh, is home to more than 400 million Muslims.

Muqadas Haider, a senior police officer, said Abdul Rehman Sindhi was arrested in a joint operation between police and intelligence agencies late on Thursday.

"Abdul Rehman Sindhi is an old veteran of al Qaeda," Haider said. "He had stayed in touch with Osama bin Laden and Ayman al- Zawahri and has worked with Harkat-ul Jihad Islami, Jaish-e-Mohammad and Al Akhtar Trust," he said.

Sindhi was put on a U.N. Security Council sanctions list in 2012 for providing "facilitation and financial services to al Qaeda".